Traditionally, as seen from FIG. 42, where communication is executed between an information processing equipment A and an information processing equipment B, the communication is not executed directly but executed through a predetermined server. In this communication, if the information processing equipment A transmits information to the relay server, the relay server receives the information and transmits it to the information processing equipment B. When the information processing equipment B receives the information transmitted from the relay server, the information transmission from the information processing equipment A to the information processing equipment B is executed. Likewise, the information transmission from the information processing equipment B to the information processing equipment A is executed through the relay server.
Such communication using the relay server is adopted in the case where audio or video data are relayed from the one information processing equipment to the other information equipment. Further, such a communication format is the communication executed until Peer-to-Peer communication is started by e.g. the SIP (Session Initiation Protocol) or STUN (Simple Traversal of UDP Through NATs). It is also adopted in the communication in which the information necessary in the Peer-to-Peer communication is transmitted or received between the information processing equipments. This communication is described in J. Rosenberg, J. Weinberger, C. Huitema, R. Mahy, “STUN—Simple Traversal of User Datagram Protocol (UDP) Through Network Address Translators (NATs)” March, 2003, Networking Group Request for Comments: 3489 (retrieved on Oct. 7, 2004, Internet URL: http://www.ietf.org/rfc/rfc3489.txt).
However, such a communication format presents a problem that if many information processing equipments execute the communication through the relay server, the processing burden on the relay server becomes excessive
On the other hand, if the data relay between the information processing equipments is executed through a plurality of relay servers in order to disperse the processing burden of the relay server, the equipment on the side of reception cannot know the relay server through which the data relay is executed and so cannot know the relay server to be accessed. Particularly, where the information processing equipment executes the communication through a communication processing equipment having a function of NAT (Network Address Translation) (e.g. device called a router), a packet is periodically transmitted to the relay server so that the information from the relay server can be received. Therefore, where the information processing equipment executes the communication through the communication processing equipment having the NAT function and the plurality of relay servers are employed in order to disperse the processing burden on the relay servers, the information processing equipment on the side of reception cannot know the relay server of the plurality of severs, through which the information is transmitted from the other information processing equipment and so cannot know the relay server to which the packet must be periodically transmitted.
Further, in order that information transmitted can be received through all the relay servers, the information processing equipment on the side of reception must transmits the packet to all the relay serves. Thus, the burden of packet transmission in the information processing equipment becomes excessive.